Stability Prediction Of Hezha Landslide In Upper Reaches Of Bailongjiang Under The Action Of Reservoir Water Level

The occurrence of landslide under the action of reservoir water level is uncertain,harmful and destructive,which is a very common natural disaster.In order to predict the stability of Heiza landslide under the action of reservoir water level,this paper firstly collected relevant geological data through field investigation,understood the engineering geological conditions of the landslide area,analyzed the basic characteristics of the landslide,determined the physical and mechanical parameters of the slip zone soil through laboratory tests,and then established the true three-dimensional model consistent with the actual terrain.Finally,the deformation characteristics of landslide under different working conditions such as natural state,stable water level,water level rising at different speeds and water level falling at different speeds were analyzed by numerical simulation.The stability of landslide was analyzed mainly from the perspectives of seepage field,displacement field and strain field with pore water pressure,displacement amount and maximum shear strain increment.Finally,the landslide stability is predicted by synthesizing the change rule of stability coefficient.The following conclusions are drawn in this paper:(1)Through the field investigation and the relevant engineering geological data collection research found that the plane shape of Heiza landslide is a"dustpan"shape,the terrain is low in the northeast and high in the southwest,the slope is steeper between 40 and 80°,belonging to the mountain canyon landform,the landslide front elevation is 1745m,the rear edge elevation is 2300m,the relative height difference between the front and back edge is large.The volume is about 8.1×10~7m3,which is a super-large accumulation landslide.(2)The results show that the stability coefficient of Hezha landslide under natural working conditions is 1.232,which is in a stable state.When the water level is stable at 1745m,the stability coefficient is 1.197,which is in a stable state.When the water level is stable at 1804m,the stability coefficient of landslide is 1.102,which is basically stable.The overall displacement and maximum shear strain increment of the landslide have little change after the rise of water storage level,and the stability coefficient decreases.When the water level rises at the same speed,the overall displacement and maximum shear strain increment of the landslide increase slowly and their variation range is small,and the stability coefficient shows a large-small-large change process,and the stability decreases on the whole.When the water level rises at different speeds,at the same water level elevation,the higher the water level rising speed,the larger the overall displacement and maximum shear strain increment of the landslide,the smaller the stability coefficient,and the overall stability decreases.When the water level drops at the same speed,the overall displacement and maximum shear strain increase gradually,and the stability coefficient decreases gradually,and the stability becomes worse.When the water level drops at different speeds,the larger the water level drops at the same water level elevation,the larger the overall displacement and maximum shear strain increment gradually,the smaller the stability coefficient,and the worse the stability.